Y/N POV

Y/N: When I will grow up, I will be like you!

???: Is that so? But be careful, this isn't a path everyone can follow, are you sure?

Y/N: Yes! I will be a Great Hero!

???: Then, let's make a contract, both of us

Mash: Master?

I opened my eyes, and see Mash, looking at me curious, as I smiled

Y/N: Ah, Mash, thank you for waking me up. It's quite the toll to fight Servant after all

Mash: Yes, it is harder than what I thought, but I feel that with you, I can beat them

Y/N: Well, if you are at my side, Mash, we both are invincible, Fou Included

Fou: Fou!

Mash: Thank you, Master!

Y/N: So, where are the Director and the servant?

Mash: They are on the roof, talking

Y/N: I see......... Maybe they're talking about the plan

Narrator POV

Olga: A Human fusing with a Grand Servant........ An Homunculus can hold the pressure of a Servant, but a Human....... You are not joking, aren't you?

Caster: Nah, I'm not. And by how the Kid fight, I would go for either Saber, or Rider, by how agile he is

Olga: Romani, any news on Y/N's mana?

Romani: Nothing, it's like something is blocking our analyze......

Olga: Tch..... I will face him myself

???: Face who?

She stopped in her track, when she saw Y/N walk past her, a smile on his face

Olga: Y-Y-

Y/N: Say, Caster, you haven't said anything bad about me in my back, right?

Caster: Huh? Who do you take me for? This Golden Bastard?

Y/N: He says insult, but he always told them in the face of the said one, no matter who they are, but I trust you here!

Olga: W-What Grand Servant are you?! Are you the Rider Grand Servant?!

Y/N: Well, you got it right on one point! I am a Grand Servant, but I am not the Rider Grand Servant!

Olga: How can a Human fuse with a Grand Servant?! The pressure would kill you!

Y/N: Hmmm....... I don't know, maybe you should try it!

Olga: Stop fooling around! Tell us who you are!

Y/N dropped his smile, before he looked at her, his eyes glowing a little

Y/N: Do you really think it's good to use that tone with me?

She took a step back, as Y/N continue

Y/N: I will only finish this singularity, and then go on my own. Until then, I promise I won't bring any harm to any of you

Olga: ........

Caster: Through all of my years of Servant, I learned something. A Grand Servant promise isn't something to take lightly. If he said it, he will keep it

Romani: And by far, he is our greatest addition in our rank. Having a Grand Servant on our side, that is also a Demi-Servant, is really something formidable

Olga: I....... I trust you, until we finish that mission

Y/N: Good! Now, how about we go and give a visit to Saber? She may be waiting for us after all

Caster: Fine by me

Mash: I will follow you, Master

Olga: Seriously, in what mess did I got in again.......

Y/N: Alright, I will state the Plan! Caster, Archer is protecting the entry, right?

Caster: Want me to take care of him?

Y/N: Yes, and when you're finished, join us instantly. Me, Mash, Director and Fou will go and face the King directly

Caster: You can take her on?

Y/N: You bet I can!

Romani: What about the other servants roaming around the city?

Y/N: Oh, we can just ignore them, and if they come to us, I handle it

Caster: Plan is fine by me

Mash: I am ready!

Olga: We don't have a choice anyway.....

Fou: Fou! Kyu!

Y/N: Alright, everyone! Let's go!

Timeskip - Y/N POV

We were running toward where Saber was waiting, before Caster stopped in his track, and turn around

Y/N: I leave it to you!

Caster: Alright!

We keep running, before we came to a stop, and see her, waiting for us

???: So you have come, at last

Mash: The king of Knights.......

Olga: Arthur Pendragon........

Y/N: She may look intimidating, but she won't be able to kill any of you until I'm here

Salter: Oh? Such confidence in your talk, but can you action prove it?!

She jump in front of us, and instantly, she got to the big deal

Salter: Excalibur-!

Y/N: Mash!

Mash: Yes!

She readied her shield, as Saber finally unleashed it

Salter: Morgan!

She unleashed the ray, hitting the shield directly, as I supported Mash against Excalibur Morgan

Mash: I-It's too strong!

Y/N: Don't fall!

She looked at me, as I clenched her hand, smiling

Y/N: We are the last stand, if we fall, it's over! Don't hesitate! If you're not hesitant, you will be able to do anything!

Her eyes widened, before she smiled back, and yell

Mash: YES!

Suddendly, her shield glowed, before her Noble Phantasm appeard, creating a wall, deflecting Excalibur Morgan

Salter: This shield......?

Mash: I did it, Master!

Y/N: Yes, I'm proud of you, now rest, I take care of it

She nodded, before I walked forward, closing my eyes

Y/N: A contract?

???: Yes, it will make me share my strengh with you, so you can protect everyone

Y/N: But you're going to disappear!

???: I may disappear, but I will always be with you, ok?

Y/N: Ok........

We shared a hand shake, as he smiled at me, before he started to disappear

???: Starting from today, you, Y/N L/N, will become the next Grand Servant, to protect Mankind, your class is.........

I opened my eyes, and smile, but before I could start, Caster appear at my side, and smirk

Caster: Heh, guess you won't have to do anything after all! Wicker Man!

A giant of wood appeard below Saber, and started to attack her

He finally grabbed her, throwing her inside his stomach, and fall on the ground, exploding

After the dust settled, we saw Saber still standing

Salter: Victory for the power that protects? I see, such like that innocent one

She smiled and started to disappear

Salter: Ultimately, no matter how fates changes, I face the same end when I'm alone

Caster: What does that mean? You know something, aren't you?

Salter: One day you will know, Ireland's child of light........ Grand Order, and the battle over the Grail has just begun

Caster started to disappear too, as he sigh

Caster: Hey kid, next time make sure to summon me as a Lancer

Y/N: Don't blame me if I summon you as a Caster again

Caster: Heh, cocky brats

He finally disappeard, as I sigh, and Fou jump on my shoulder

Fou: Fou!

Y/N: Yup, it's our victory!

Mash: Yes! We did it, Director!

Olga: Yes, you did well, all of you

Before we could celebrate more, claps were heard

???: My, I never thought you get this far. This is an unforeseen element of the project that goes beyong what my tollerance allows

Mash: Proffessor Leff.......?

Olga was about to run toward him, but I grabbed her hand, stopping her

Olga: What are you doing?! It's Leff!

Y/N: I know, and that's why I am keeping you here. Romani said that he was in the middle of the explosion, right? Then how could he be alive, and this well?

Leff: Well, such a troublesome but smart brat. You understood quickly about it

Olga: H-Huh?

Y/N: Mash, protect the Director, I take care of this

Leff: Olga, I planted the bomb right under your feet, I can't believe you're still alive

Olga: W-What?

Leff: But it have no importance, because all of you will die here!

He created a portal behind him, using the power of the Grail, as Olga started to fly toward it

Inside the portal was the engine used for the Rayshift

Leff: This is no different from a Blackhole, or the sun even? Either way, if a Human touch it, they will be split apart on molecular level. You will live an infinite death loop

Olga: Please, someone save me!

She keep crying, before she appeard at our side, as I kneel in front of her

Y/N: Director, calm down, ok? Like I said, until I'm here, no one will die. You did your best, I take care of it. Grand Servant Saber, Y/N, at your order

Leff: You again? I should kill you no-

He stopped in the middle of his sentence, as he saw me in front of him, fist ready

Y/N: This one's really going to hurt

I punched him a dozen of time in the gut, before low kick his leg, and kick him toward the sky

An earthquake happened, as Leff suddendly disappear, as I turn toward Mash and Olga, and grab them

I looked at Fou, as he jumped on my shoulder, and hold tight

Y/N: Hold tight!

I keep running from the EarthQuake, as I got outside, and saw the whole Singularity falling appart

Y/N: Romani!

Romani: Beggining the Rayshift!

A sudden light blinded me, as I landed back in Chaldea, Olga and Mash passed out

Romani: Rayshift Success!

People started to cheer, while I laid Mash and Olga on the ground, and sigh

Y/N: Close one. I think I'm able to handle a Singularity fall, but these two wouldn't be able to

Romani: Y/N, can I have a talk with you?

Y/N: Sure, what is it about?

Romani: It's about Olga.........

Timeskip - Narrator POV

Olga started to wake up, and slowly sat up, rubbing her head

Olga: What happened...........

She suddendly remembered the betrayal of Leff, and grabbed her arm, shivering

Olga: I-It was a nightmare, Leff would never do that........

???: Sadly, it is the truth, Director

She looked at her side, and see Romani smiling sadly at her, while Y/N was playing chess with Da Vinci

Da Vinci: Checkmate

Y/N: Again?! It's the 4th time in a row! I call cheat!

Da Vinci: Call me Master Da Vinci and I will teach you how to play!

Y/N: NEVER! REVENGE!

Olga: Romani........ What happened?

Romani: Well, after Leff betrayal, Y/N took you and Mash out of the Singularity that was breaking and falling apart

Olga: What about Leff..........?

Y/N: I kicked his ass, but he ran away before I could land the finishing blow

Da Vinci: Checkmate

Y/N: AAAAAAAAAAAAAAAAAAh!

Romani: But there is more important things right now, Director. It's about the Rayshift effect. We learned that after the first Rayshift, your body wasn't physical, or at least, not fully

Olga: H-Huh?

Romani: When we passed exam, we came to conclusion that if you went out of the Singularity, your body would have disappeard, but it didn't happened

Olga: H-How?! What happened?!

Romani: It's all thanks to him. He used his mana to create a whole body for you to live in, and able to endure Rayshift

He pointed at Y/N, who was thinking hard on the Chess game

Olga: How? He said he was a Grand Servant, but his class is Saber, not caster, so how........

Romani: Well.........

Y/N: HAHA! I WON!

Da Vinci: Oh no, I lost. Sike, Checkmate again

Y/N: WHAT?!

Romani: He lied about him being the Saber Grand Servant....... He actually is the Rider Grand Servant

Olga: ..............

She didn't say anything, except getting up , and walk toward Y/N, who saw her, and got up too

Y/N: Sup

Olga didn't say anything, before hugging him out of the blue, as Romani and Da vinci looked at each other, and nodded, walking out of the room

Y/N: Uh......... Don't cry?

Olga: Did you mean it?

Y/N: What?

Olga: What you said back then....... Did you mean it?

Y/N: I mean everything I say, so yeah.......... I did......?

Olga got a huge smile, but hide on Y/N's chest, before breaking out of the hug, and cough

Olga: I-I admit I have misjudged you at first! But now we need to work together to save Mankind!

Y/N: Yes Ma'am!

Olga: A-And I need you at my side for that!

Y/N: Well I won't leave it anytime soon

Olga: Eh?

Y/N: If a Grand Servant is summoned, it means a Beast is threatening Humanity. And so, I have to take care of it

Olga smiled widely, before she walked out of the room, back to her confident self

Olga: Alright, everyone, it's time for Chaldea to counter attack!

All: YES!

A/N: Yup, Olga is the promised one of Y/N, and YES I'M GIVING HER RESPECT BECAUSE SHE DESERVED BETTER!

And yes Y/N is Grand Servant Rider :D